Small blood vessels.
D000818:Animals; D001001:Anura; D001775:Blood Circulation; D001808:Blood Vessels / Q000033:anatomy & histology* / Q000503:physiopathology; D001921:Brain / Q000098:blood supply; D002196:Capillaries / Q000033:anatomy & histology* / Q000503:physiopathology; D002415:Cats; D002675:Child, Preschool; D002685:Chiroptera / Q000033:anatomy & histology; D006224:Cricetinae; D004285:Dogs; D006801:Humans; D008297:Male; D051379:Mice; D011651:Pulmonary Artery / Q000033:anatomy & histology; D011667:Pulmonary Veins / Q000033:anatomy & histology; D011817:Rabbits; D051381:Rats; D014921:Wings, Animal / Q000098:blood supply